Raspberry Pi 400 Keyboard PC Review and Benchmarks vs Raspberry Pi 4

Raspberry Pi 400 Review vs Raspberry Pi 4

Raspberry Pi 400 keyboard computer with Broadcom BCM2711C0 1.8 GHz processor has just launched, and we already published a teardown of the Raspberry Pi 400 hardware to check out the cooling solution and overall hardware design.

In this review, we’ll mostly focus on Raspberry Pi 400 and Raspberry Pi 4 differences, since both devices mostly rely on the same chips. After checking the different features, we’ll run Thomas Kaiser’s “SBC Bench” script to test thermal cooling and benchmark both RPi hardware platforms.

Raspberry Pi 400 vs Raspberry Pi 4 Model B Features

Since under the hood, the two platforms are very similar, we’ll highlight the difference as shown in the table below courtesy of Cytron.

Raspberry Pi 400 vs Raspberry Pi 4 Model B

Price is not shown in the table above, but Raspberry Pi 400 costs $70, while Raspberry Pi 4 with 4GB goes for $55. That’s $15 extra for a keyboard, case, and cooling solution, so the price is very attractive.

Stock performance is a little higher thanks to a 1.8 GHz processor, but as we’ve seen in the past it’s always possible to overclock Raspberry Pi 4 to 2.0+ GHz provided you’ve got a proper cooling solution.

The keyboard PC adds a… keyboard as one should expect, with US, UK, DE, FR, IT, or ES layout, a power button that enables soft power on/off and may help to prevent file system corruption, as well as a Kensington Lock hole to protect again theft, for example at school. IMHO, it’s a more portable solution, than having a keyboard and Raspberry Pi 4 + heatsink or fanless case.

Having said that, you’ll lose some features including the CSI camera and DSI display connectors, PoE, the 3.5mm audio jack, and one USB 2.0 port. The latter is not really a problem, as in many cases, it would be used by an external USB keyboard.

Raspberry Pi OS System Info

The keyboard computer is software-compatible with Raspberry Pi 4, so I could just install Raspberry Pi OS 32-bit released last August for the review.

Raspberry Pi 400 Raspberry Pi OS

The user experience is exactly the same as in Raspberry Pi 4, so let’s check out some of the system information:

No differences here, except or the revision code – c03130 – with “13” being the code for Raspberry Pi 400 and the first “0” meaning it’s manufactured by Sony UK.

Mostly the same as Raspberry Pi 4, except for the 1.8 GHz frequency, and the cool 39.4°C system temperature in a room at 28°C. That also means it’s a candidate for overclocking, but I have not tried it in this review

Raspberry Pi 400 Benchmarks and Thermal Testing

I’ve installed both rpimonitor and SBC Bench for this section. Here are the results:

No throttling as been detected, and the temperature chart shows why:

Raspberry Pi 400 Temperature Chart

It started around 37°C at idle and peaked a little over 50°C during 7-zip multi-threaded benchmarks.

I won’t compare it to bare a Raspberry Pi 4 since we know how it goes, but instead to a Raspberry Pi 4 with KKSB fanless metal case @ 1.5 and 2.0 GHz.

Raspberry Pi 4 Fanless Metal Case Temperature
Raspberry Pi 4 @ 1.5 GHz with KKSB case
Raspberry Pi 4 2-GHz CPU Temperature KKSB Case
Raspberry Pi 4 @ 2 GHz with KKSB Case

Note the charts above were produced in February 2020 with the latest firmware that included all recent optimizations for cooling and lower power consumption. Needless to say, the results are impressive as Raspberry Pi 400 is equipped with an adequate cooling solution.

Now let’s compare the benchmarks results (higher is better) and max temperatures (lower is better):

Raspberry Pi 400 @ 1.8 GHzRaspberry Pi 4 @ 1.5 GHzRaspberry Pi @ 2.0 GHz
memset (MB/s)2675.42662.52749.1
memcpy (MB/s)3107.43436.93849.9
OpenSSL (hash/s)
AES-256-CBC - 16KB
Max temperature (°C)51.665.280.3

7-zip and OpenSSL mostly follow the CPU frequency, but somehow memset and memcpy show lower memory bandwidth in Raspberry Pi 400. The keyboard PC is better at cooling thanks to the large heat spreader that almost matches the results with active cooling.

Raspberry Pi 400 and HAT expansion boards

Raspberry Pi 400 comes with the traditional 40-pin header which can easily be used with jumper cables, or a 40-pin ribbon cable to HAT expansion boards. But I don’t own the latter, so I wonder if I could somehow plug a HAT directly into the keyboard. I dusted off RabbitMax Flex Pi HAT to give it a try.

Raspberry Pi 400 HAT

Raspberry Pi 400 40-pin expansion board

Pin 1 and Pin 40 are clearly marked on the keyboard, so it’s easy to plug it correctly, but depending on the model it may not fit perfectly, as some pins from the add-on board may prevent full insertion.

add-on board does not fit

If your HAT board does not have pins on the bottom side around one centimeter above the 40-pin header it should be OK. Nevertheless, it’s probably a better idea to get a ribbon cable.

Final words

I have to say I’m impressed, the Raspberry Pi Foundation has done a great job here. Raspberry Pi 400 keyboard PC comes with most goodies from Raspberry Pi 4, but you don’t have to mess with cases or heatsinks for cooling, it just works great out of the box, and I’m sure it will be popular especially in education settings. It’s also priced aggressively at just over $15 an equivalent Raspberry Pi 4 SBC with 4GB RAM, or about the price – or even lower in some cases – of a fanless Raspberry Pi metal case.

It’s not for everyone though. First, it’s not practical/suitable for embedded projects where the single board computer form factor remains ideal. Educators must keep in mind that any projects relying on the Raspberry Pi camera and/or display will not be possible, nor any project with PoE, although I’d kind of like the concept of a PoE powered keyboard PC…

I’d like to thank Cytron for sending a review sample. They sell Raspberry Pi 400 keyboard computer and ship it worldwide for $70 plus taxes and shipping.

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